This invention pertains to caulking guns for dispensing mastic compounds. More particularly, it pertains to a caulking gun capable of using disposable caulk tubes of different diameters, in the same caulking gun.
Caulking guns are used to apply sealants and adhesives, hereafter referred to as mastic compounds, when installing windows and doing general caulking and bonding on buildings. Caulking guns used by tradesmen to apply mastic compound fall into one of two general types. The first type is a bulk dispensing gun which is a complete unit unto itself, comprising a closed refillable cylindrical chamber containing a spout, a plunger within the cylinder and an actuating means to move the plunger forward to dispense the mastic compound from the cylinder.
The second type of caulking gun found in today's market place, is one that has an open frame structure to support a single disposable caulking tube and an actuating mechanism designed to move a push rod assembly for dispensing the mastic compound contained in the disposable caulking tube. The push rod assembly consists of a single push rod with a single thrust disk attached to one end of the push rod. The current common open frame caulk tube gun, hereafter referred to as the “C-gun”. Each C-gun is currently designed hold one specific size disposable caulk tube having a plastic spout on one end and a movable plunger on the opposite end. The present invention is concerned with the C-gun, and in the following discussion the term “caulking gun” should be understood as referring to a C-gun type caulking gun.
Currently only two C-gun type sizes are commercially available. One C-gun has a nominal cradle length of 23 cm (9 inches) and is sized to receive a 0.35 liter (12.8 fluid ounce) caulk tube with an inside diameter of approximately 4.6 cm. (1 13/16 inches). This tube size is referred to hereafter as “size A” tube. The second C-gun with a nominal cradle length of 13 inches is sized to receive a 0.95 liter (32 fluid ounce) disposable caulk tube which has an inside diameter of approximately 6.2 cm (2 7/16 inches). This tube size is referred to hereafter as “size B” tube. The length of each conventional C-gun is designed to receive only one specific size disposable caulk tube; either a “size A” caulk tube or a “size B” caulk tube. Also, the diameter of the thrust disk on each conventional C-gun is intentionally designed to be used exclusively with the plunger in either a “size A” caulk tube or “size B” caulk tube. To the inventors' knowledge no one offers a C-gun having a single thrust disk capable of fitting into the inside diameter of plungers for a “size A” and a “size B” disposable caulk tube. Also no one offers a C-gun capable of using disposable caulk tubes with different outside diameters within the same C-gun cradle.
Since the introduction of disposable caulking tubes (1920's), there have been only two standard size disposable caulk tubes available in general commerce, a small size (size A) and a large size (size B). The small size has a body length of 20.3 to 21.6 cm. (8.0 to 8.5 inches), and has an outer diameter of 4.4 to 5.1 cm (0.1.75 to 2.0 inches), and has a net content of approximately 0.31 liters (10.5 fluid ounces) of mastic compound (the 0.38 liter (12.8 fluid ounce gross capacity of the caulk tube is not completely filled with mastic). The large size has a body length of 31 to 31.8 cm (12.25 to 12.50 inches), and has an outer diameter of 6 to 6.7 cm (2.38 to 2.63 inches), and has a net content of approximately 0.9 liter (30 fluid ounces) of mastic compound. These two disposable caulk tubes are currently the only disposable caulk tube sizes produced for use in C-guns sold to the general public and tradesmen using mastic compounds. However, the inventors have developed a new novel size disposable caulk tube that has the diameter of the “size B” disposable caulk tube and the body length of the “size A” disposable caulk tube. This novel sized caulking tube, which is the subject of pending application Ser. No. 10/886,178, is referred to hereafter as a “size C” caulk tube.
Because size A disposable caulk tubes are being sold and size C disposable caulk tubes will soon be on the market, there is a need for having single C-gun capable of receiving either a size A and a size C caulk tube. The C-gun of this invention is designed to receive only one tube at a time, and is easily adept at receiving either a size A or a size C disposable caulk tube (as selected by the user). In its simplest embodiment, this novel C-gun accepts either a size A or C caulk tube with no adjustments being required. The benefits of having a multi-purpose C-gun capable of holding a single tube of either “size A” or “size C” caulk tubes is realized in the economics of manufacturing (one gun serving two purposes) and in the broader utility embodied in a single multi-purpose C-gun that is compatible with multiple sizes of disposable caulk tubes, which will benefit workmen applying mastic compound.
It is an object of the present invention to embody within one multi-purpose C-gun the capability of dispensing mastic compounds from either a standard “size A” disposable caulk tube or the novel “size C” disposable caulk tube.